Image processing apparatus

ABSTRACT

An image processing apparatus includes a scanner configured to read an image formed on a sheet along a reading direction and generate image data thereof, and a processor. The processor is configured to select a first region of the generated image data into which a first image indicating the reading direction is to be combined, set a pixel value of the first image in accordance with a pixel value of a pixel around the first region, and combine the first image having the determined pixel value into the first region of the image data and output the combined image data.

FIELD

Embodiments described herein relate generally to an image processingapparatus and an image processing method.

BACKGROUND

To determine a cause of a malfunction or perform maintenance of an imageprocessing apparatus, such as an MFP (multi-function printer), it issometimes necessary to obtain information indicating the reading(scanning) direction or the printing direction for a document page(sheet) or the like. In such cases, for example, a user may sometimesmark an arrow on the sheet for indicating the orientation of the sheetduring reading or printing. Information indicating the sheet directionor orientation is sometimes found in a work report prepared by arepairman or technician.

However, if the direction indicated by an arrow written by a user iswrong or a report prepared by a repairman lacks information about thedirection, it takes longer for maintenance work.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external view of an image processing apparatus according toan embodiment.

FIG. 2 is a hardware block diagram of an image processing apparatus.

FIG. 3 is a diagram illustrating an internal structure of a printer.

FIG. 4 is a diagram illustrating an example of a document sheet.

FIG. 5 is a diagram illustrating combined image data in whichreading-direction images are combined.

FIG. 6 is a diagram illustrating image data in which a reading-directionimage is not combined correctly.

FIG. 7 is a diagram illustrating combined image data after correction;

FIG. 8 is a diagram illustrating a sheet on which image data is printedwithout magnification.

FIG. 9 is a diagram illustrating a sheet on which image data is reducedand printed.

FIG. 10 is a diagram illustrating a sheet on which an image is expandedand printed.

FIG. 11 is a diagram illustrating a sheet on whichimage-forming-direction images are printed.

FIG. 12 is a diagram illustrating a sheet on which animage-forming-direction image and a reading-direction image are printed.

FIG. 13 is a diagram illustrating a sheet on which animage-forming-direction image and a reading-direction image are printed.

FIG. 14 is a flowchart of a process of combining read images.

FIG. 15 is a flowchart of a process of combining a reading-directionimage and an image-forming-direction image in copying.

FIG. 16 is a diagram illustrating a symbol and a peripheral region.

FIG. 17 is a diagram illustrating a symbol with a color having asaturation less than a threshold.

FIG. 18 is a diagram illustrating a symbol with a color having asaturation greater than a threshold.

FIG. 19 is a flowchart of a color determination process.

FIG. 20 is a diagram illustrating a plurality of divided regions.

FIG. 21 is a flowchart of a combined region determination processthrough white determination.

FIG. 22 is a flowchart of a combined region determination processthrough saturation determination.

FIG. 23 is a diagram illustrating a pattern image indicating areading-direction image.

DETAILED DESCRIPTION

In general, according to one embodiment, an image processing apparatusincludes a scanner configured to read an image formed on a sheet along areading direction and generate image data thereof, and a processor. Theprocessor is configured to select a first region of the generated imagedata into which a first image indicating the reading direction is to becombined, set a pixel value of the first image in accordance with apixel value of a pixel around the first region, and combine the firstimage having the determined pixel value into the first region of theimage data and then output the combined image data.

An image processing apparatus according to certain example embodimentswill be described with reference to the drawings.

FIG. 1 is an external view of an image processing apparatus 1 accordingto an embodiment. FIG. 2 is a hardware block diagram of the imageprocessing apparatus 1. For example, the image processing apparatus 1 isan image forming apparatus such as an MFP. The image processingapparatus 1 includes a main control unit 100, a sheet storage unit 140,an operation panel 200, a scanner 300, and a printer 400. The imageprocessing apparatus 1 forms an image on a sheet using developer. Thedeveloper is, for example, toner. In the following description, thedeveloper is a toner as one example. A sheet is, for example, a papersheet or a label sheet. In general, any sheet type may be used as longas the image forming apparatus 1 can form an image on the surface of thesheet.

The operation panel 200 includes one or more operation keys 202 and adisplay unit 203. The operation panel 200 accepts an operation from auser. The operation panel 200 outputs a signal to the main control unit100 in response to the operation that has been input by the user.

The display unit 203 is an image display device such as a liquid crystaldisplay or an organic electro luminescence (EL) display. The displayunit 203 displays various kinds of information regarding the imageforming apparatus 1.

The printer 400 forms an image on a sheet based on image data generatedby the scanner 300 or image data received via a network. The printer 400forms such an image using toner. A sheet on which an image is to beformed may be stored in the sheet storage unit 140 or fed manually bythe user. In the following description, forming of an image is alsoexpressed as printing of an image.

The sheet storage unit 140 stores sheets on which an image is to beformed by the printer 400.

The scanner 300 reads a reading target image and records it as readimage data. The recorded image data may be transmitted to anotherinformation processing device via a network. The image indicated by therecorded image data may be formed on a sheet by the printer 400.

Next, with reference to FIG. 2 , the image processing apparatus 1includes the main control unit 100, the operation panel 200, the scanner300, and the printer 400. The image processing apparatus 1 includes amain CPU (central processing unit) 101 of the main control unit 100, apanel CPU 201 of the operation panel 200, a scanner CPU 301 of thescanner 300, and a printer CPU 401 of the printer 400.

The main control unit 100 includes the main CPU 101, a ROM (read onlymemory) 102, a RAM (random access memory) 103, a NVRAM (nonvolatile RAM)104, a network controller 105, an HDD (hard disk drive) 106, a modem107, a page memory (PM) 109, a page memory control unit 110, and animage processing unit 111.

The main CPU 101 controls the entire operation of the image processingapparatus 1. The ROM 102 stores data such as a control program necessaryfor the control. The RAM 103 temporarily stores data. The NVRAM 104 is anonvolatile memory.

The network controller 105 connects the image processing apparatus 1 toa network. The image processing apparatus 1 communicates with, forexample, an external device such as a server or a personal computer (PC)via the network controller 105. The HDD 106 stores data such as an imageto be formed on a sheet or an image read by the scanner 300. Of theimage data stored in the HDD 106, information indicating a readingresolution in a reading operation and a recording resolution recorded inthe HDD 106 is included in a header of the image data read by thescanner 300. The modem 107 connects the image processing apparatus 1 toa telephone line.

The page memory 109 stores image data corresponding to each of aplurality of pages. The page memory control unit 110 controls the pagememory 109. The image processing unit 111 performs image processing onthe image data. Specific examples of the image processing include acolor conversion process, a color range correction process, a sharpnessadjustment process, gamma correction and halftone processing, and pulsewidth modulation (PWM) processing. The image processing unit 111 may beimplemented using hardware such as an application specific integratedcircuit (ASIC) or may be implemented as software executed by the mainCPU 101.

The operation panel 200 includes the panel CPU 201, the operation keys202, and the display unit 203. The panel CPU 201 controls the operationpanel 200. The panel CPU 201 is connected to the main CPU 101 via a bus.If an instruction for display is received from the main CPU, the panelCPU 201 generates a screen for the display unit 203 in response to thereceived instruction. If a numerical value, a user selection of aprocess for execution, or setting information is input via one or moreof the operation keys 202, the panel CPU 201 outputs corresponding datato the main CPU 101. The operation keys 202 permit the input of userselections, the setting information, the numerical values, and the like.Specific examples of information received by an operation key 202include various instructions or settings such as a size and direction ofa sheet on which an image is to be formed or a magnification of imageformation. The display unit 203 is a display device such as a liquidcrystal display or an organic EL display. The display unit 203 may beconfigured as a touch panel.

The scanner 300 includes the scanner CPU 301, an image correction unit302, a reading control unit 303, a charge coupled device (CCD) 304, andan auto document feeder (ADF) 305. The scanner CPU 301 controls thescanner 300. The image correction unit 302 includes, for example, an A/Dconversion circuit, a shading correction circuit, and a line memory. TheA/D conversion circuit converts analog signals of R, G, and B outputfrom the CCD 304 into digital signals. The ADF 305 is an auto documentconveyance unit. The ADF 305 picks up and conveys a sheet set by a useralong a conveyance path in a conveyance direction. The ADF 305 conveysthe sheet by rotating a conveyance roller along the conveyance path andthe CCD 304 reads an image on the sheet which is being conveyed.

The printer 400 includes the printer CPU 401, a laser driver 402, aconveyance control unit 403, and a control unit 404. The printer CPU 401controls the printer 400. The laser driver 402 drives a laser to form anelectrostatic latent image on a photoreceptor. The conveyance controlunit 403 conveys a sheet which is an image forming target. The controlunit 404 controls the laser driver 402 such that an image is formed onthe sheet conveyed by the conveyance control unit 403.

FIG. 3 is a diagram illustrating the internal structure of the printer400. In the example of FIG. 3 , the printer 400 is a four-tandem typeprinter. Here, the printer 400 is not limited to the four-tandem typeprinter.

The printer 400 includes an image forming unit 10, a fixing unit 30, anda discharging unit 40. The image forming unit 10 includes anintermediate transfer body 11, developing devices 91 to 94, a pluralityof primary transfer rollers 17 (17-1 to 17-4), a secondary transfer unit18, and an exposure unit 19.

The intermediate transfer body 11 is, for example, an endless belt. Theintermediate transfer body 11 is rotated in a direction indicated by anarrow 1010 by a roller. In this disclosure, upstream and downstreamsides are defined according to the direction in which the intermediatetransfer body 11 moves in normal operation. Visible images generated bythe developing devices 91 to 94 are transferred to the surface of theintermediate transfer body 11.

The developing devices 91 to 94 form visible images using toner withdifferent properties. For example, toner of different colors may be usedin the developing devices 91 to 94. For example, toners with colors ofyellow (Y), magenta (M), cyan (C), and black (K) may be used. In some ofthe developing devices 91 to 94, toner which can be later decoloredafter initial printing by an external stimulus (for example, heat) maybe used. In some of the developing devices 91 to 94, a special tonersuch as glossy toner or fluorescent toner may be used.

In FIG. 3 , of the four developing devices 91 to 94, the developingdevice 91 is located most upstream and the developing device 94 islocated most downstream.

The developing devices 91 to 94 store toners with different propertiesbut each of the developing devices 91 to 94 have the same basicstructure. The developing device 91 includes a developing unit 121, aphotosensitive drum 131, a charger 141, a cleaning blade 151, and adeveloping drum 161. The developing device 92 includes a developing unit122, a photosensitive drum 132, a charger 142, a cleaning blade 152, anda developing drum 162. The developing device 93 includes a developingunit 123, a photosensitive drum 133, a charger 143, a cleaning blade153, and a developing drum 163. The developing device 94 includes adeveloping unit 124, a photosensitive drum 134, a charger 144, acleaning blade 154, and a developing drum 164.

The developing device 91 will be explained as structurally andfunctionally representative of the other developing devices 92, 93, and94. The developing device 91 includes the developing unit 121, thephotosensitive drum 131, the charger 141, the cleaning blade 151, andthe developing drum 161. The developing unit 121 stores toner andcarrier therein. The developing unit 121 attaches the toner to thephotosensitive drum 131 by the developing drum 161.

The photosensitive drum 131 includes a photoreceptor on its outercircumference. The photoreceptor is, for example, an organicphotoconductor (OPC). The photosensitive drum 131 is exposed by theexposure unit 19 and forms an electrostatic latent image on the surface.

The charger 141 uniformly charges the surface of the photosensitive drum131.

The cleaning blade 151 is, for example, a plate member. The cleaningblade 151 is formed of, for example, a rubber such as a urethane resin.The cleaning blade 151 removes the toner attached on the photosensitivedrum 131.

Next, an overall operation of the developing device 91 will bedescribed. The photosensitive drum 131 is charged with a predeterminedpotential by the charger 141. Subsequently, the photosensitive drum 131is radiated with light from the exposure unit 19. Thus, a potential ofthe region radiated with the light is changed on the photosensitive drum131. Due to this change, an electrostatic latent image is formed on thesurface of the photosensitive drum 131. The electrostatic latent imageon the surface of the photosensitive drum 131 is subsequently developedwith the toner of the developing unit 121. That is, a visible image (animage formed with toner) is formed on the surface of the photosensitivedrum 131.

At the primary transfer rollers 17 (17-1 to 17-4), the developingdevices 91 to 94 transfer the visible images respectively formed on thephotosensitive drums 131 to 134 to the intermediate transfer body 11.

The secondary transfer unit 18 includes a secondary transfer roller 181and a secondary transfer counter roller 182. The secondary transfer unit18 transfers the visible images from the intermediate transfer body 11to a sheet. The transferring in the secondary transfer unit 18 can beimplemented by, for example, generation of an electrical potentialdifference between the secondary transfer roller 181 and the secondarytransfer counter roller 182.

The exposure unit 19 forms an electrostatic latent image by radiatingthe photosensitive drums 131 to 134 of the developing devices 91 to 94with light. The exposure unit 19 includes a light source such as a laseror a light-emitting diode (LED). In the present embodiment, the exposureunit 19 includes a laser and operates under the control of the laserdriver 402.

The fixing unit 30 fixes the visible images (toner images) to a sheet byheating and pressing the visible images on the sheet. The dischargingunit 40 discharges the sheet after the sheet has been fixed in thefixing unit 30 to the outside of the image processing apparatus 1.

Next, a reading-direction image that indicates a reading direction andan image-forming-direction image that indicates an image formingdirection will be described. The reading-direction image and theimage-forming-direction image are images used by a repairman executingmaintenance, inspection, or the like of the image processing apparatus 1to easily identify the reading direction and the image forming directionof the image processing apparatus 1. If the reading direction or theimage forming direction can be easily identified, the time and effortnecessary to determine a fault or malfunction of the image processingapparatus 1 can be considerably reduced than would otherwise be thecase.

The reading-direction image is an image indicating a reading directionin which a document sheet is read by the scanner 300. When a documentsheet is scanned in the image processing apparatus 1, thereading-direction image indicating the reading direction in the scanner300 is combined with image data that is read from the document.Specifically, the combination is performed as follows. The imageprocessing unit 111 of the main control unit 100 combines thereading-direction image with image data generated through scanning. Theimage processing unit 111 records the image data combined with thereading-direction image in the HDD 106.

The reading direction in the scanner 300 is a sub-scanning direction ofa line sensor and is a direction from one of four sides of the documentfinally read by the line sensor towards the opposite side first read bythe line sensor.

Accordingly, the reading direction is uniquely determined, for example,if the side (edge) of a document that has been read first is specified.Accordingly, the reading-direction image is an image used to specify theone of the four sides of a document sheet that has been first read bythe line sensor. FIG. 4 is a diagram illustrating an example of adocument sheet 500. Of four sides of the document sheet 500, the sidefirst read by the scanner 300 is denoted by the reference numeral 510.

FIG. 5 is a diagram illustrating combined image data 600 in whichreading-direction images 601 are combined. In the combined image data600, the reading-direction images 601 are combined. In the example ofFIG. 5 , two symbols (for example, rectangles, specifically, squares)are arranged along a direction perpendicular to the reading direction.However, if the reading direction can be determined, any number ofsymbols having any shape may be used as the reading-direction image(s)601. In the combined image data 600, a side 610 corresponds to the side510 of the document sheet 500. The side 610 is specified with thereading-direction images 601 configured in combination of two symbols (apair). Thus, the reading direction is easily identifiable.

The image data of a document sheet is recorded in the HDD 106 with aresolution different from a resolution during reading of the documentsheet in some cases. For example, a resolution during reading of thedocument sheet is 600 dpi and a resolution of the image data recorded inthe HDD 106 is 300 dpi in some cases. In such cases, if thereading-direction image is combined as it is, a part of thereading-direction image may be lost.

FIG. 6 is a diagram illustrating image data in which a reading-directionimage is not combined correctly. Since the resolution decreases, theimage recorded in the HDD 106 is smaller than the original image.Therefore, as illustrated in FIG. 6 , a symbol 603 that is a combinedreading-direction image remains, whereas the other symbol 604 is outsidethe image data and is not combined.

Accordingly, the image processing unit 111 determines a position atwhich each reading-direction image is disposed and a size of thereading-direction image based on a reading resolution and a recordingresolution so that any reading-direction image is not lost. Correctionof a combination position and correction of the size of thereading-direction image are expressed as a reading-direction imagecorrection process together. Hereinafter, an example of thereading-direction image correction process will be described.

If the reading resolution and the recording resolution are the same,coordinates of combination positions of the symbols of thereading-direction images are (XPOS1, YPOS1) and (XPOS2, YPOS2). Thereading resolution is IN_DPI and the recording resolution is OUT_DPI. Acorrection coefficient K is OUT_DPI/IN_DPI. When the reading resolutionand the recording resolution are the same, the lengths of thereading-direction image in the transverse direction and the longitudinaldirection are XSIZE and YSIZE.

The image processing unit 111 derives (K×XPOS1, K×YPOS1) and (K×XPOS2,K×YPOS2) as coordinates of the corrected combination positions. Theimage processing unit 111 derives K×XSIZE and K×YSIZE as the lengths ofthe reading-direction image corrected in the transverse direction andthe longitudinal direction as coordinates of the corrected combinationpositions. For example, if IN_DPI is 600 dpi and OUT DPI is 300 dpi, thecorrection coefficient is 0.5. Therefore, each reading-direction imageis a symbol with half the size in the transverse and longitudinaldirections.

FIG. 7 is a diagram illustrating combined image data after correction.As illustrated in FIG. 7 , the sizes of symbols 605 and 606 of thereading-direction images are further corrected according to the reducedresolution of the image data. In this way, even if the readingresolution and the recording resolution are different, the readingdirection can also be specified. When the image data is printed, thereading resolution is set to the original. Thus, since the size of thereading-direction image is restored to the original size, thereading-direction image can be maintained with a constant size.

Next, reading-direction images combined during copying will bedescribed. During copying, a document sheet is first read, magnification(image expansion or reduction) is performed in accordance with adesignated magnification ratio, and printing is performed on a sheetwith the designated size. If the position or the size of thereading-direction image is changed in accordance with the magnification,a repairman is unlikely to be able to determine whether an image printedon the sheet is an original image on the document sheet or areading-direction image. Whether to perform magnification and themagnification ratio are recorded in the RAM 103. The image processingunit 111 determines whether to perform magnification, and the like withreference to the RAM 103.

Accordingly, if an image is magnified and is formed on a sheet, theimage processing unit 111 combines the reading-direction image with theimage data without changing a position at which the reading-directionimage is combined and the size of the reading-direction image.

FIG. 8 is a diagram illustrating a sheet on which image data is printedwithout magnification. FIG. 9 is a diagram illustrating a sheet on whichimage data is reduced and printed. FIG. 10 is a diagram illustrating asheet on which image data is expanded and printed.

FIGS. 8, 9, and 10 each illustrate printing performed without changingthe position at which each symbol 620 of the reading-direction image iscombined and the size of each symbol 620 of the reading-direction image.In this way, a repairman can determine whether an image printed on thesheet is an original image or a reading-direction image.

Next, combination of an image-forming-direction image indicating animage forming direction with image data will be described. Here, theimage forming direction is a conveyance direction of a sheet passingthrough the secondary transfer unit 18.

For example, the image forming direction is uniquely determined if theside (edge) of a sheet first passing through the secondary transfer unit18 is specified. In such a case, the image-forming-direction image is animage with which the side first passing through the secondary transferunit 18 is specified among four sides of the sheet. The conveyancedirection of the sheet is determined in accordance with a direction ofthe sheet in the sheet storage unit 140. Accordingly, the imageprocessing unit 111 generates image data in which theimage-forming-direction image is combined in accordance with thedirection of the sheet in the sheet storage unit 140. The direction ofthe sheet is recorded in the RAM 103 for each cassette of the sheetstorage unit 140. The image processing unit 111 records the combinedimage data in the HDD 106. The image data recorded in the HDD 106 isoutput to the printer 400.

FIG. 11 is a diagram illustrating a printed sheet 630 on whichimage-forming-direction images are printed. In FIG. 11 , of four sidesof the printed sheet 630, a side first passing through the secondarytransfer unit 18 is a side 631. The side 631 is specified with twosymbols 632 configuring the image-forming-direction images. In this way,the image forming direction is easily specified.

As illustrated in FIG. 11 , each image-forming-direction image 632 iscircular. That is, the reading-direction image and theimage-forming-direction image have different shapes. However, thoseimages may also or instead be different in size, color, density,pattern, or the like.

The image processing unit 111 combines the image-forming-direction imagewith the image data without changing the size of theimage-forming-direction image even if the image is magnified and printedon a sheet. Thus, a repairman can determine whether the image printed onthe sheet is an image originally formed on a document sheet or theimage-forming-direction image.

The image processing apparatus 1 can also perform printing by combiningthe image-forming-direction image and the reading-direction image. FIGS.12 and 13 are diagrams illustrating a sheet on which bothimage-forming-direction images and reading-direction images are printed.In the examples illustrated in FIGS. 12 and 13 , the sizes of the sheetsare A4. In the examples illustrated in FIGS. 12 and 13 , the readingdirection is a longitudinal (long dimension) direction of A4.

In the examples illustrated in FIGS. 12 and 13 , the directions of thesheets in the sheet storage unit 140 are different by 90°. Specifically,the direction of the sheet in the example illustrated in FIG. 12 is adirection in which a conveyance direction of the sheet is thelongitudinal direction of A4. The direction of the sheet in the exampleillustrated in FIG. 13 is a direction (A4-R) in which the conveyancedirection of the sheet is perpendicular to the longitudinal direction ofA4.

Accordingly, in the example illustrated in FIG. 12 , the readingdirection is the same as the image forming direction. Therefore,reading-direction images 651 and image-forming-direction images 652 arecombined in the same direction. In the example illustrated in FIG. 13 ,however, the reading direction is different from the image formingdirection. Therefore, the reading-direction images 651 and theimage-forming-direction images 652 are combined in different directions.Thus, since the reading direction and the printing direction can beeasily identified, it is possible to considerably reduce the time andeffort necessary for a repairman to inspect a fault.

As illustrated in FIGS. 12 and 13 , the reading-direction images 651 andthe image-forming-direction images 652 are combined without overlapping.For example, two patterns of combination positions of theimage-forming-direction images are prepared. In one of the patterns, thepositions of the image-forming-direction images are preset for a case inwhich only the image-forming-direction images are combined. In the otherpattern, the positions of the image-forming-direction images and thereading-direction images are preset so as not to overlap each other.Thus, the image processing unit 111 can combine the reading-directionimages and the image-forming-direction images without overlapping.

Aspects of the above-described processes will be described withreference to certain flowcharts. FIG. 14 is a flowchart of a process ofcombining read images. The scanner 300 performs a scanning process(ACT101). The image data obtained through the scanning process isrecorded in the page memory 109. The image processing unit 111 performsimage processing on the image data recorded in the page memory 109 andrecords the image data in the HDD 106 (ACT102).

The image processing unit 111 acquires a reading resolution and arecording resolution from the image data recorded in the HDD 106(ACT103). The image processing unit 111 determines whether the acquiredreading resolution and recording resolution are different (ACT104). Ifthe reading resolution is the same as the recording resolution (NO inACT104), the image processing unit 111 causes the process to proceed toACT106. If the reading resolution is different from the recordingresolution (YES in ACT104), the image processing unit 111 performs areading-direction image correction process (ACT105) such as describedabove.

The image processing unit 111 next combines the reading-direction image(ACT106). If the reading-direction image correction process isperformed, the image processing unit 111 combines the reading-directionimage at the position or with the size derived in the reading-directionimage correction process. If the reading resolution is the same as therecording resolution, the image processing unit 111 combines thereading-direction image at the position or with the size in accordancewith the reading resolution.

The image processing unit 111 then records the combined image data inthe HDD 106 (ACT107) and ends the process.

FIG. 15 is a flowchart illustrating a process of combining areading-direction image and an image-forming-direction image in copying.The scanner 300 performs a scanning process (ACT201). The image dataobtained through the scanning process is recorded in the page memory109. The image processing unit 111 performs image processing on theimage data recorded in the page memory 109 and records the image data inthe HDD 106 (ACT202).

The image processing unit 111 determines whether magnifying is beingperformed in the copying (ACT203). If the copying is to be performedwithout magnifying (NO in ACT203), the image processing unit 111 causesthe process to proceed to ACT205. If magnifying is to be performed inthe copying (YES in ACT203), the image processing unit 111 next performsthe magnifying process (ACT204). The magnification ratio or the like canbe recorded in the RAM 103. The image processing unit 111 then combinesthe reading-direction image (ACT205).

The image processing unit 111 acquires a direction (orientation) of asheet in the sheet storage unit 140 (ACT206) on which an image is to beprinted. The image processing unit 111 combines theimage-forming-direction image in accordance with the acquired direction(ACT207). The image processing unit 111 records the combined image datain the HDD 106 (ACT208). The image processing unit 111 converts theimage data recorded in the HDD 106 into printing image data (forexample, raster data) and outputs the converted image data to theprinter 400.

The printer 400 performs printing using the input image data (ACT209)and then ends the process.

Next, a color determination process for determining pixel color valuesof the reading-direction image will be described. If thereading-direction image is combined with the image data generatedthrough scanning, the reading-direction image may be hidden, obscured,or invisible depending on the combined region. For example, thereading-direction image may be hidden by the color(s) of the surroundingregions around the reading-direction image having a color that matches(or substantially so) the color of the reading-direction image.

If the reading-direction image is hidden or obscured by the combinedimage data, it will be difficult for a person to view thereading-direction image on the sheet that is printed. Thus, if the imageprocessing unit 111 of the main control unit 100 combines thereading-direction image with the image data, the color of thereading-direction image can be set or adjusted in accordance with thepixel values of the pixels adjacent or near the region in which thereading-direction image is provided.

A method of setting a color of the reading-direction image will bedescribed. In order for the reading-direction image not to be hidden,the image processing unit 111 may change or set the color of thereading-direction image so that the color is different from a color ofthe pixels around the combined region.

The image processing unit 111 acquires the pixel values of the pixelsaround the combined region(the region with the reading-direction imagetherein). In the following description, the reading-direction image isconfigured as a solid symbol and the region adjacent to the solid symbolis referred to as the peripheral region.

FIG. 16 is a diagram illustrating a symbol 700 and a peripheral region710. As illustrated in FIG. 16 , the peripheral region 710 has a frameshape and surrounds the symbol 700.

The size of the peripheral region 710 can be set such that the symbol700 within the peripheral region 710 can be visually distinguished by aperson. For example, the thickness of the frame portion of theperipheral region 710 may be set to about 2 mm.

The image processing unit 111 acquires pixel values of the pixels in theperipheral region 710. For example, pixel values are expressed as red,green, and blue (RGB) values. The peripheral region 710 includes N totalpixels and pixel values of these pixels are expressed as Pi=(ri, gi, bi)(where 1≤i≤N). Here, ri is a red pixel value (R value) of the i^(th)pixel, gi is a green pixel value (G value) of the i^(th) pixel, and biis a blue pixel value (B value) of the i^(th) pixel.

The image processing unit 111 calculates an average value of Pi. In sucha case, the average value r of the red pixel values is (r1+ . . .+rN)/N. The average value g of the green pixel values is (g1+ . . .+gN)/N. The average value b of the blue pixel values is (b1+ . . .+bN)/N. The image processing unit 111 sets the calculated average value(r, g, b) as the color corresponding to the peripheral pixels.

The image processing unit 111 checks that the color of the symbol isdifferent from the calculated average (r, g, b) of the peripheralpixels. A color that is different from calculated average (r, g, b) is acolor for which at least one of red value, green value, or blue value isdifferent from the calculated average value (r, g, b). The imageprocessing unit 111 may set the color of the symbol to be acomplementary color corresponding to the peripheral pixel average values(r, g, b) by predetermined values. For example, the image processingunit 111 may obtain the complementary color by inverting or switchingRGB values. The complementary color may be obtained by switching “a”component and “b” component of the calculated average value projectedinto a Lab color space.

The image processing unit 111 may determine that the color of the symbol700 is to be a color having a saturation less than a threshold if thesaturation of the pixels of the peripheral region is greater than thethreshold. For example, the threshold can be set in advance and storedin the NVRAM 104. A color with a saturation less than the threshold tobe used for the color of the symbol may be stored in the NVRAM 104 ormay be appropriately calculated or set in accordance with calculatedaverage values (r, g, b) of the peripheral region pixels.

FIG. 17 is a diagram illustrating the symbol 700 with a color having asaturation less than the threshold. In FIG. 17 , a saturation of theperipheral region 710 is assumed to be greater than the threshold. Insuch a case, the image processing unit 111 determines that the color ofthe symbol 700 is to be a color with a saturation less than thethreshold. Thus, since the symbol 700 is not hidden amongst theperipheral region 710, a repairman or an engineer can visually check areading direction.

The image processing unit 111 may alternatively determine that the colorof the symbol is to be a color having a saturation greater than thethreshold if the saturation of the pixels of the peripheral region 700is less than the threshold. For example, the relevant threshold can beset in advance stored in the NVRAM 104. RGB values for the color with asaturation greater than the threshold to be used for the symbol 700 mayalso be stored in the NVRAM 104 or may be appropriately calculated orset in accordance with the calculated average pixel values of theperipheral region 700.

FIG. 18 is a diagram illustrating the symbol 700 with a color having asaturation greater than a threshold. In FIG. 18 , the saturation of theperipheral region 710 is less than the threshold. In such a case, theimage processing unit 111 determines that the color of the symbol 700 isto be a color with a saturation greater than the threshold.

FIG. 19 is a flowchart of the above-described color determinationprocess. The image processing unit 111 acquires a peripheral color(ACT301). The peripheral color is color expressed with the pixel valuesof the pixels of the peripheral region. The image processing unit 111determines whether the color of a symbol is to be determined based on asaturation of the peripheral color (ACT301). As methods of setting thecolor for a symbol 700 or the like, there is a method of setting thecolor based on saturation level of the peripheral region 710 and amethod of setting the color for the symbol 700 to be a complementarycolor of the average color value of the peripheral region 710. Themethod of setting the color for the symbol 700 can be preset by a userand the relevant setting stored in the NVRAM 104. The image processingunit 111 performs the determination of ACT304 with reference to thesetting stored in the NVRAM 104.

If the color is to set in accordance with saturation (YES in ACT302),the image processing unit 111 next determines whether the saturation ofthe peripheral color is greater than a threshold Sth (ACT303). If thesaturation of the peripheral color is greater than the threshold Sth(YES in ACT303), the image processing unit 111 sets the color of thesymbol 700 to have a saturation less than the threshold, (ACT304) andthen ends the process.

If the saturation of the peripheral color is equal to or less than thethreshold Sth (NO in ACT303), the image processing unit 111 sets thecolor of the symbol 700 to have a saturation greater than the threshold,(ACT305) and then ends the process.

If the color of the symbol 700 is to be selected as a complementarycolor rather by saturation (NO in ACT302), the image processing unit 111sets the color of the symbol 700 to be a complementary color of theperipheral color (ACT306) and then ends the process.

In the above-described example, a plurality of reading-direction imagesin different forms may be provided. For example, the reading-directionimages in the different forms may be combined so that image dataobtained from a document sheet placed on a platen glass can bedistinguished from image data obtained via the ADF 305. If the ADF 305can perform a double-sided reading of a document sheet,reading-direction images in the different forms may be combined so thatimage data obtained from the front surface of the document sheet can bedistinguished from image data obtained from the rear surface.

Next, a combined region determination process will be described. Asdescribed above, if a reading-direction image is combined with imagedata generated by scanning, the reading-direction image may be hiddendepending on position of the combined region with respect to the scannedimage.

Accordingly, the image processing unit 111 may potentially select aposition/placement for the reading-direction image in accordance withpixel values in the scanned image data. In this process, the color to beused for the symbol 700 can be set in a color determination processbased on surrounding pixels of the selected position/placement for thesymbol 700 or otherwise may be a fixed value.

The image processing unit 111 may select the position/placement for thecombined region from among a plurality of candidate regions. FIG. 20 isa diagram illustrating a plurality of candidate regions obtained bydividing a region of the image data into a plurality of regions. FIG. 20illustrates nine candidate regions 801, 802, 803, 804, 805, 806, 807,808, and 809. The candidate regions illustrated in FIG. 20 are merelyone example. The number of candidate regions is not necessarily limitedto nine and the shape and arrangement of the regions are not limited tothe example of FIG. 20 either. The candidate regions may even overlapeach other in part.

The image processing unit 111 first acquires the color (e.g., theaverage color value (r, g, b)) of the candidate region 801. If thesymbol 700 would be hidden if placed in candidate region 801, the imageprocessing unit 111 searches for another candidate region in which thesymbol 700 would not be hidden if placed therein. The search order ofthe candidate regions may be the numerical order of the candidateregions 802, 803, 804, 805, 806, 807, 808, and 809 or any other order.The candidate region in which the symbol would not be hidden if placedtherein, are each referred to in this context as a combinable region.

One of the combinable regions (eligible candidate regions) may be a“white” region, where “white” need not mean completely white (truewhite; RGB (255, 255, 255)). That is, the color such a combinable regionmay be a color that is substantially white or near white.

Specifically, the color determination of the combinable regions can beperformed using a threshold Rth compared to a pixel value of red, athreshold Gth compared to a pixel value of green, and a threshold Bthcompared to a pixel value of blue. For example, these thresholds are setin advance and stored in the NVRAM 104. For example, each of Rth, Bth,and Gth is set to “230.”

The image processing unit 111 determines whether the color (r, g, b) ofa candidate region satisfies r>Rth, g>Gth, and b>Bth. This determinationis referred to as a “white determination”. The image processing unit 111determines that the candidate region is to be used if the whitedetermination is positive (values exceed the thresholds). If the whitedetermination is negative (values do not exceed the thresholds), theimage processing unit 111 performs the white determination on asubsequent candidate region.

If the white determination is negative for all the candidate regions,the image processing unit 111 selects the candidate region for which thevalue r+g+b is the largest. The image processing unit 111 may thenperform the above-described color determination process on the candidateregion 801 and add the symbol 700 of an appropriately selected color tothe candidate region 801.

The image processing unit 111 may check whether the saturation of thecolor (r, g, b) of the candidate regions is less than a threshold. Thisis referred to as “saturation determination”. The image processing unit111 checks whether a candidate region has a positive saturationdetermination (pixel value exceeds the threshold). If the saturationdetermination is negative, the image processing unit 111 performs thesaturation determination on the next candidate region.

If the saturation determination is negative for all the candidateregions, the image processing unit 111 may select the candidate regionfor which the saturation is the smallest. The image processing unit 111may perform the color determination process on the selected candidateregion and add the symbol 700 to the candidate region.

FIG. 21 is a flowchart of the above-described combined regiondetermination process through the white determination. In the flowchart,k-th (where k=1 to 9) candidate regions correspond to the regions 801,802, 803, 804, 805, 806, 807, 808, and 809.

In FIG. 21 , the image processing unit 111 initializes a loop counter kto “1” (ACT401). The image processing unit 111 acquires the color of thek-th candidate region (ACT402). The image processing unit 111 performsthe white determination process on the acquired color of the k-thcandidate region (ACT403). If the k-th candidate region is white (YES inACT404), the image processing unit 111 selects the k-th candidate region(ACT408) and ends the process.

If the result of the white determination is negative (NO in ACT404), theimage processing unit 111 increments loop counter k (ACT405). The imageprocessing unit 111 checks whether k is greater than “9” (ACT406). If kis equal to or less than “9” (NO in ACT406), the image processing unit111 causes the process to proceed to ACT402 to perform the whitedetermination on the next candidate region. If k is greater than “9”(YES in ACT406), the white determination has been performed on all theavailable candidate regions. Accordingly, the image processing unit 111selects the candidate region for which the sum (r+g+b) in is the largest(ACT407) and then ends the process.

FIG. 22 is a flowchart of the combined region determination process bysaturation determination. In the flowchart, the k-th (where k=1 to 9)candidate regions correspond to the regions 801 to 809 as depicted inFIG. 20 .

In FIG. 22 , the image processing unit 111 initializes the loop counterk to “1” (ACT501). The image processing unit 111 acquires the saturationof the k-th candidate region (ACT502). The image processing unit 111performs a saturation determination for the candidate region (ACT503).If the saturation of the k-th candidate region is less than thethreshold (YES in ACT504), the image processing unit 111 selects thiscandidate region (ACT508) and then ends the process.

If the saturation determination is negative (NO in ACT504), the imageprocessing unit 111 increments the loop counter k (ACT505). The imageprocessing unit 111 checks whether k is greater than “9” (ACT506). If kis equal to or less than “9” (NO in ACT506), the image processing unit111 causes the process to proceed to ACT502 to perform the saturationdetermination on the next candidate region. If k is greater than “9”(YES in ACT506), the saturation determination has been performed on allthe available candidate regions. The image processing unit 111 theselects the candidate region for which the saturation is the smallest(ACT507) and then ends the process.

In the present embodiment, the symbol may be a pattern type imageindicating a reading-direction image. FIG. 23 is a diagram illustratingsuch a pattern type image to be used as a reading-direction image. Inthe example of FIG. 23 , a pattern image with vertical lines is used asa reading-direction image. Then, for example, a repairman or an engineercan visually check a reading direction since it is easy to distinguishthe symbol.

The color determination process and combined region determination(selection) process may be combined. Specifically, if there is anyrestriction on the color of the symbol and it checked in the colordetermination whether the symbol having one of the acceptable colors forthe symbol would be hidden, the image processing unit 111 may performthe combined region determination process based on the possible colorsof the symbols.

If the determination is positive in ACT406 or ACT506 of the combinedregion determination process, the image processing unit 111 may thenperform the color determination process.

In this way, if the color determination process and the combined regiondetermination process are combined, a probability of the symbol notbeing hidden is higher than if the color determination process and thecombined region determination process are not combined.

The color determination process and the combined region determinationprocess are performed according to the image data obtained throughscanning, but similar processes may be applied to print data (e.g., aprint file or a print job including image data such as that acquiredfrom an external device or the like).

The main CPU 101 and the image processing unit 111 may be integratedinto a single processor. The image processing device may not include theprinter 400.

According to the above-described embodiment of the image processingdevice 1, it is possible to provide the image processing device capableof easily identifying a reading direction.

While certain embodiments have been described these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. An image processing apparatus, comprising: ascanner configured to read an image formed on a sheet along a readingdirection and generate image data; and a processor configured to: selecta first region of the generated image data into which a first imageindicating the reading direction is to be combined, set a pixel value ofthe first image in accordance with a pixel value of a pixel around thefirst region, and combine the first image having the set pixel valueinto the selected first region of the image data and output the combinedimage data.
 2. The image processing apparatus according to claim 1,wherein the pixel value of the first image indicates a first color thatis different from a second color indicated by the pixel value of thepixel around the first region.
 3. The image processing apparatusaccording to claim 2, wherein the first color is a complementary colorof the second color.
 4. The image processing apparatus according toclaim 1, wherein the processor is further configured to: determinewhether a saturation of color of the first region is greater than athreshold, upon determining that the saturation is greater than thethreshold, set the pixel value of the first image to have a saturationless than the threshold, and upon determining that the saturation is notgreater than the threshold, set the pixel value of the first image tohave a saturation greater than the threshold.
 5. The image processingapparatus according to claim 1, wherein the first image includes apattern of images arranged along the reading direction.
 6. The imageprocessing apparatus according to claim 1, the processor is furtherconfigured to: acquire a first resolution that has been used by thescanner to read the image and a second resolution that is used to storethe generated image data in a storage device, and before combining thefirst image, correct a location of the first region when the first andsecond resolutions are different.
 7. The image processing apparatusaccording to claim 1, further comprising: a printer configured to printan image on a sheet along a printing direction, wherein the processor isfurther configured to: select a second region of the generated imagedata into which a second image indicating the printing direction is tobe combined based on a location of the first region in the generatedimage data, combine the second image into the second region of the imagedata, and output the combined image data to the printer.
 8. The imageprocessing apparatus according to claim 7, wherein the first and secondimages have different shapes.
 9. The image processing apparatusaccording to claim 7, wherein the processor is further configured toexpand or reduce the image data according to a designated magnificationratio for printing, and the first and second regions are selected suchthat the first and second regions will be printed on a sheet.
 10. Theimage processing apparatus according to claim 7, wherein the first andsecond images each include two symbols separated from each other in adirection perpendicular to the reading direction or the printingdirection, respectively.
 11. An image processing apparatus, comprising:a scanner configured to read an image formed on a sheet along a readingdirection and generate image data thereof; and a processor configuredto: determine a plurality of candidates of a first region of thegenerated image data into which a first image indicating the readingdirection is to be combined; determine a pixel value for each of thecandidates and select one of the candidates as the first region based onthe determined pixel value; and combine the first image into the firstregion of the image data and output the combined image data.
 12. Theimage processing apparatus according to claim 11, wherein the processorselects, as the first region, one of the candidates having a pixel valuecorresponding to or closest to white.
 13. The image processing apparatusaccording to claim 11, wherein the processor selects, as the firstregion, one of the candidates having a saturation of color less than athreshold.
 14. The image processing apparatus according to claim 11,wherein the processor is further configured to divide the generatedimage data into a plurality of regions to form the candidates of thefirst region.
 15. The image processing apparatus according to claim 11,wherein the first image includes a pattern of images arranged along thereading direction.
 16. The image processing apparatus according to claim11, wherein the processor determines the pixel value for each of thecandidates by calculating an average of pixel values of pixels includedin said each of the candidates.
 17. An image processing method,comprising: reading an image formed on a sheet along a reading directionand generating image data thereof; selecting a first region of thegenerated image data into which a first image indicating the readingdirection is to be combined; setting a pixel value of the first image inaccordance with a pixel value of a pixel around the first region;combining the first image having the set pixel value into the firstregion of the image data and outputting the combined image data.
 18. Theimage processing method according to claim 17, wherein the set pixelvalue of the first image indicates a first color that is different froma second color indicated by the pixel value of the pixel around thefirst region.
 19. The image processing method according to claim 18,wherein the first color is a complementary color of the second color.20. The image processing method according to claim 17, furthercomprising: determining whether a saturation of color of the firstregion is greater than a threshold; upon determining that the saturationis greater than the threshold, setting the pixel value of the firstimage to have a saturation less than the threshold; and upon determiningthat the saturation is not greater than the threshold, setting the pixelvalue of the first image to have a saturation greater than thethreshold.